MrCJ

Is there an easy way to get a rough piston to valve clearance measurement?

The methods I have seen require the heads to be taken on and off and require solid lifters (which I don't have), which seems a bit full on, or a whole heap of math, which seems prone to error.

Is it worth using a variant of the clay method with the hydraulic lifters, and adding a bit of error margin, or is the piston to valve clearance on an LS2 with a big cam so close that I need the accuracy of solid lifters?

I know plenty of people change cams without removing the heads, so I guess they are just hoping for the best, but if there is some sort of sanity check I can easily do, please let me know.

brandon6.0

iTrader: (32)

This is how i measure: No head removal needed!

I remove the int. and exh. valve springs for one cylinder. I install a set of weaker cheap springs. Checker springs they are called. I then install the factory rockers with pushrods as if it was a complete engine.

I thin mount my dial indicater to the head and adjust it on the tip of the rocker. I finally rotate motor till tht rocker is at full bottom travel. (As in valve completely open).

Thin push the valve all the way open past the rockers travel until valve hits piston. Record measurement. This is your ptv clearance for tht valve. This is the true way to check ptv. No geuss work!

ColeGTO

iTrader: (3)

The point at which the valve is closest to the piston is not at max. lift. It is usually around 8-12 degrees BTDC (before top dead center) for the exhaust valve and 8-12 degrees ATDC (after top dead center) for the intake valve. Some cams might be slightly off from there, but it will be "around" there. I start at 15 degrees before/after TDC and check every 1 degree just to be sure.

The reason for using a "solid" lifter is that the hydraulic lifter plunger can colapse and it will show more piston to valve clearance than you have and you could run into REALLY big problems.

Sure, there are ways to "cut corners", but verifying piston to valve clearance is rather important and should be done properly.

98CayenneT/A

This is the way I did it and very simple
https://ls1tech.com/forums/generatio...ve-method.html

ColeGTO

iTrader: (3)

That looks pretty easy. I think I'll take the time to do it this way next time along with the conventional method and compare the results.

MrCJ

That is awesome, thanks!

I guess with no pressure being on the lifters, I guess that method would work with hydraulic lifters too.

pantera_efi

iTrader: (1)

Hi MrCJ, I use an EAP model to first check P/V distance.

I will do this for free, all LS-1 Tech members INCLUDED !

I need the valve train info, Valve Drop, A lobe file is best (a doctor OR Andrews file) AND Head Gasket thickness.

I test at Split Overlap, though an easy change if required ?

Lance, BTW this IS an EASY method !